A1c Calculator

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A1C Calculator (eAG Conversion)
Calculate eAG (mg/dL) from A1CCalculate eAG (mmol/L) from A1CCalculate A1C (%) from eAG (mg/dL)
Result:
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Calculator Use

This a1c calculator is a professional tool designed to help individuals with diabetes and healthcare providers convert between Hemoglobin A1C percentages and Estimated Average Glucose (eAG) values. Understanding the relationship between these two metrics is essential for effective blood sugar management and long-term health tracking.

By using the a1c calculator, you can translate your 3-month lab result (A1C) into the familiar mg/dL or mmol/L units used by daily glucose monitors, or vice versa.

A1C Percentage (%)
This is a blood test that measures your average blood sugar levels over the past 2 to 3 months. It represents the percentage of hemoglobin that has glucose attached to it.
Estimated Average Glucose (eAG)
eAG is a calculated value that converts your A1C into the same units used by home glucose meters (mg/dL or mmol/L), making the 3-month average easier to compare with daily readings.

How It Works

The a1c calculator uses the ADAG (A1C-Derived Average Glucose) study formula, which is the standard clinical method for converting these values. The relationship is linear, meaning as A1C increases, the average blood sugar increases at a predictable rate.

eAG (mg/dL) = (28.7 × A1C) – 46.7

To find the A1C from a known average glucose, the formula is rearranged:

A1C (%) = (eAG + 46.7) / 28.7

  • 28.7: The slope coefficient representing the change in glucose per 1% change in A1C.
  • 46.7: The intercept constant derived from the clinical study data.
  • mg/dL: Milligrams per deciliter, the standard unit in the United States.
  • mmol/L: Millimoles per liter, the standard unit in the UK, Canada, and Australia (calculated by dividing mg/dL by 18.0182).

Calculation Example

Example: A patient receives a lab report showing an A1C level of 7.0%. They want to know what their average daily blood sugar was in mg/dL.

Step-by-step solution:

  1. Identify Input: A1C = 7.0
  2. Apply Formula: eAG = (28.7 × 7.0) – 46.7
  3. Multiply: 28.7 × 7.0 = 200.9
  4. Subtract: 200.9 – 46.7 = 154.2
  5. Result: 154 mg/dL (Estimated Average Glucose)

Common Questions

Why is my daily average different from the A1C calculator result?

Daily averages from a glucose meter only reflect the times you test (usually before or after meals). The A1C measures glucose 24 hours a day, including while you sleep. Most people test less frequently when their blood sugar is stable, which can cause daily averages to appear lower or higher than the 3-month average.

What is a normal A1C level?

For individuals without diabetes, a normal A1C range is typically between 4% and 5.6%. An A1C of 5.7% to 6.4% indicates prediabetes, and 6.5% or higher indicates diabetes. However, targets vary by individual, so always consult a medical professional.

How often should I use the A1C calculator?

Because A1C represents a 90-day average, using the a1c calculator to predict lab results is most effective when you have at least 2-4 weeks of consistent data from a Continuous Glucose Monitor (CGM) or frequent finger-prick testing.

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